Iran's state TV has broadcast the apparent confession of a man it describes as "the main element" of an Israeli-trained network involved in the assassination of an Iranian scientist last year.

The young man, identified as Majid Jamali-Fash, said last night that he was hired by Israel and trained at a military base outside Tel Aviv before being dispatched to Iran as a part of network ordered to kill Masoud Ali-Mohammadi, a Tehran University particle physicist.

Mohammadi was blown up outside his house last January when a remote-control bomb that had been attached to a motorcycle parked on the street detonated in a northern suburb of Tehran.

Jamali-Fash claimed that he was briefed about Mohammadi in Israel and was given detailed instructions of the assassination plot "in a military camp situated in the highway between Tel Aviv to Jerusalem".

"Two new Iranian-made motorbikes were there [In Israel] … They told me where to go, where to stop, who to call and how to do things back in Iran," he said.

At the time of the assassination, it was not immediately clear whether Mohammadi was involved in Iran's nuclear activities, and speculation was rife over the reasons for his killing when it emerged that he was a supporter of the Iranian opposition. But later it was revealed that he was a member of an Iranian team at the Sesame Council, a joint project involving different countries including Israel which runs a particle accelerator in Jordan.

According to the Iranian intelligence minister, Heidar Moslehi, who said Iran had uncovered a US-backed Israeli operation and arrested Mohammadi's assassins, Jamali-Fash was not the only one linked to Mossad. Speaking to reporters in Tehran, he said: "More than 10 people were arrested in connection with different networks." He did not give any further information about the arrests.

"The intelligence system of the Islamic Republic of Iran has achieved a remarkable triumph and intelligence supremacy over the Zionist regime's [Israeli's] espionage system and we succeeded in identifying enemy's elements," Moslehi was quoted by the semi-official Fars news agency as saying.

Moslehi's remarks came after Iran's intelligence ministry said that Mossad was behind the assassination of Mohammadi and accused "certain neighbouring countries" of co-operation with the Israeli intelligence service.

"The regional and neighbouring countries that have interactions with Israel should pay attention that any facility they provide to the Zionist regime is considered against the region and the Islamic Republic," Moslehi warned.

Iran has also admitted in recent months that its uranium enrichment plant was affected by the Stuxnet computer worm, which targeted the industrial management software that Iran uses to run its centrifuges. All of these incidents have led to speculation last week by the former Israeli intelligence chief Meir Dagan that Iran would be unlikely to build a nuclear bomb before 2015.

Some analysts believe that the sophistication of the assassinations and the Stuxnet worm are indications that Israel might be behind the covert campaign.

Iran also signalled today that it would negotiate with six world powers over its nuclear programme on 21 and 22 January in Istanbul.

Iran maintains that its nuclear activities are peaceful and says that western countries, especially the US and Israel, are trying to prevent it from progressing technologically. The west says Iran has failed to demonstrate its peaceful intentions and has not fully co-operated with international inspectors.